opensbi/lib/utils/fdt/fdt_helper.c

// SPDX-License-Identifier: BSD-2-Clause
/*
 * fdt_helper.c - Flat Device Tree manipulation helper routines
 * Implement helper routines on top of libfdt for OpenSBI usage
 *
 * Copyright (C) 2020 Bin Meng <bmeng.cn@gmail.com>
 */

#include <libfdt.h>
#include <sbi/riscv_asm.h>
#include <sbi/sbi_console.h>
#include <sbi/sbi_platform.h>
#include <sbi/sbi_scratch.h>
#include <sbi_utils/fdt/fdt_helper.h>

static int fdt_get_node_addr_size(void *fdt, int node, unsigned long *addr,
				  unsigned long *size)
{
	int parent, len, i;
	int cell_addr, cell_size;
	const fdt32_t *prop_addr, *prop_size;
	uint64_t temp = 0;

	parent = fdt_parent_offset(fdt, node);
	if (parent < 0)
		return parent;
	cell_addr = fdt_address_cells(fdt, parent);
	if (cell_addr < 1)
		return SBI_ENODEV;

	cell_size = fdt_size_cells(fdt, parent);
	if (cell_size < 0)
		return SBI_ENODEV;

	prop_addr = fdt_getprop(fdt, node, "reg", &len);
	if (!prop_addr)
		return SBI_ENODEV;
	prop_size = prop_addr + cell_addr;

	if (addr) {
		for (i = 0; i < cell_addr; i++)
			temp = (temp << 32) | fdt32_to_cpu(*prop_addr++);
		*addr = temp;
	}
	temp = 0;

	if (size) {
		for (i = 0; i < cell_size; i++)
			temp = (temp << 32) | fdt32_to_cpu(*prop_size++);
		*size = temp;
	}

	return 0;
}

int fdt_parse_uart8250(void *fdt, struct platform_uart_data *uart,
		   const char *compatible)
{
	int nodeoffset, len, rc;
	fdt32_t *val;
	unsigned long reg_addr, reg_size;

	/**
	 * TODO: We don't know how to handle multiple nodes with the same
	 * compatible sring. Just return the first node for now.
	 */

	nodeoffset = fdt_node_offset_by_compatible(fdt, -1, compatible);
	if (nodeoffset < 0)
		return nodeoffset;

	rc = fdt_get_node_addr_size(fdt, nodeoffset, &reg_addr, &reg_size);
	if (rc < 0 || !reg_addr || !reg_size)
		return SBI_ENODEV;
	uart->addr = reg_addr;

	/**
	 * UART address is mandaotry. clock-frequency and current-speed may not
	 * be present. Don't return error.
	 */
	val = (fdt32_t *)fdt_getprop(fdt, nodeoffset, "clock-frequency", &len);
	if (len > 0 && val)
		uart->freq = fdt32_to_cpu(*val);

	val = (fdt32_t *)fdt_getprop(fdt, nodeoffset, "current-speed", &len);
	if (len > 0 && val)
		uart->baud = fdt32_to_cpu(*val);

	return 0;
}

int fdt_parse_plic(void *fdt, struct platform_plic_data *plic,
		   const char *compatible)
{
	int nodeoffset, len, rc;
	const fdt32_t *val;
	unsigned long reg_addr, reg_size;

	nodeoffset = fdt_node_offset_by_compatible(fdt, -1, compatible);
	if (nodeoffset < 0)
		return nodeoffset;

	rc = fdt_get_node_addr_size(fdt, nodeoffset, &reg_addr, &reg_size);
	if (rc < 0 || !reg_addr || !reg_size)
		return SBI_ENODEV;
	plic->addr = reg_addr;

	val = fdt_getprop(fdt, nodeoffset, "riscv,ndev", &len);
	if (len > 0)
		plic->num_src = fdt32_to_cpu(*val);

	return 0;
}

int fdt_parse_clint(void *fdt, unsigned long *clint_addr,
		    const char *compatible)
{
	int nodeoffset, rc;

	nodeoffset = fdt_node_offset_by_compatible(fdt, -1, compatible);
	if (nodeoffset < 0)
		return nodeoffset;

	rc = fdt_get_node_addr_size(fdt, nodeoffset, clint_addr, NULL);
	if (rc < 0 || !clint_addr)
		return SBI_ENODEV;

	return 0;
}